Bacterial populations found in household dust may determine whether or not a child living in that home develops asthma according to research published in the April 2010 issue of the journal Applied and Environmental Microbiology.

Recent studies have shown household dust to be a source of highly diverse and abundant bacteria, yet it remains largely unexplored. In the study, testing on samples of collected house dust demonstrated that bacterial populations are greatly impacted by the presence of dogs and cats and whether or not children attend day care. Additionally, dust samples collected from homes of infants, with or without pets and varying day care attendance, showed differences in dust bacteria were linked with asthma development in children

"These results provide the first evidence that the dominant bacterial populations in household dust are significantly influenced by environmental variables such as domestic animals and day care attendance," say the researchers. "Further, the dominant bacterial populations are significantly correlated to asthma-related outcomes, supporting the hypothesis that the types of microorganisms present in homes in early life may play key roles in the development of childhood asthma."

Asthma has risen drastically in the last decade and some are attributing the increase to an altered immune response triggered by exposure to evolving microbial communities. Farms and day care centers are associated with asthma prevention due to high levels of microbial exposure, while actions that reduce bacterial populations in the home may actually increase allergy development.

"These parallels suggest that unidentified differences in exposure to microbial communities in the industrialized world may have fundamentally changed human immune responses, thereby enhancing susceptibility to autoimmune and allergic diseases," say the researchers.